Schema Walkthrough & Types

Phi uses Prisma Schema language (schema.prisma) to define data models, relationships, field constraints, and database providers.

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1. Schema Definition Walkthrough

A minimal schema.prisma file consists of a datasource block and one or more models:

datasource db {
  provider = "postgres"
}

model User {
  id         String    @id @default(cuid())
  email      String    @unique
  phoneNum   String    @unique
  role       UserRole  @default(STUDENT)
  loginCount Int       @default(0)
  createdAt  DateTime  @default(now())
  updatedAt  DateTime  @updatedAt

  posts      Post[]

  @@unique([email, phoneNum])
}

model Post {
  id        String   @id @default(cuid())
  title     String
  content   String
  published Boolean  @default(false)
  authorId  String
  author    User     @relation(fields: [authorId], references: [id], onDelete: Cascade)
}

enum UserRole {
  ADMIN
  STUDENT
  TEACHER
}

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2. Supported Scalar Types & Go Mappings

Prisma Scalar Type	Go Client Type	Struct Field (Required)	Struct Field (Optional ?)
String	string	string	*string
Boolean	bool	bool	*bool
Int	int32	int32	*int32
BigInt	int64	int64	*int64
Float	float64	float64	*float64
Decimal	string	string	*string
DateTime	time.Time	time.Time	*time.Time
Json	json.RawMessage	json.RawMessage	*json.RawMessage
Bytes	[]byte	[]byte	*[]byte
Enum	phi.UserRoleType	phi.UserRoleType	*phi.UserRoleType

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3. Native Attributes (`@db.*`) & Provider Mappings

Phi adheres strictly to Prisma's provider-specific feature specifications:

PostgreSQL vs. SQLite Column Type Mapping

Prisma Definition	PostgreSQL SQL DDL	SQLite SQL DDL
id String @id @default(cuid())	TEXT NOT NULL	TEXT NOT NULL
id String @id @default(uuid())	TEXT or UUID	TEXT NOT NULL
field String @db.VarChar(255)	VARCHAR(255)	Not supported by Prisma schema
field String @db.Text	TEXT	Not supported by Prisma schema
field Int @id @default(autoincrement())	SERIAL / BIGSERIAL	INTEGER PRIMARY KEY AUTOINCREMENT
createdAt DateTime @default(now())	TIMESTAMP	TIMESTAMP
data Json	JSONB	TEXT / BLOB
role UserRole	Native CREATE TYPE "UserRole"	TEXT + CHECK ("role" IN (...))

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4. Scalar Array Fields in SQLite (`/// @elementType`)

PostgreSQL natively supports scalar array types (e.g. String[] -> text[]). Because SQLite does not natively support scalar array types, Prisma schema restricts String[] on SQLite providers.

To use typed scalar arrays in SQLite models, Phi supports the /// @elementType <Type> doc-comment decorator placed above a Json field defaulting to "[]":

model User {
  id   String @id @default(cuid())

  /// @elementType String
  tags Json   @default("[]")
}

• Go Client Generation: Phi generates Tags []string on the model struct and handles JSON serialization and deserialization transparently.
• SQLite DDL: Generated as a TEXT or BLOB JSON column.

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5. SQL Indexes (`@@index`)

Phi supports single-column and multi-column index declarations in schema.prisma:

model User {
  id        String   @id @default(cuid())
  email     String   @unique
  role      UserRole @default(STUDENT)
  createdAt DateTime @default(now())

  @@index([email])
  @@index([role, createdAt])
}

Migration DDL Generation

When phi migrate is executed, index definitions are calculated by the migration engine and output as standard DDL statements:

CREATE INDEX "User_email_idx" ON "User" ("email");
CREATE INDEX "User_role_createdAt_idx" ON "User" ("role", "createdAt");

Query Performance vs Unique Predicates

Non-unique @@index declarations speed up query execution (FindMany, FindFirst, Count) directly on the database engine. Because non-unique indexes can match multiple rows, they optimize SQL performance without generating FindUnique predicate handles (only @id, @unique, @@id, and @@unique generate FindUnique targets).